Patents Examined by David M. Mason
  • Patent number: 5405788
    Abstract: A method for forming semiconductor devices includes a low energy implant for tailoring the electrical characteristics of the semiconductor devices. Using the low energy implant, narrow width devices such as access transistors in an SRAM cell, can be fabricated with a low threshold voltage (Vt). The low energy implant is performed on the active areas of a silicon substrate following field isolation and field implant. For an n-conductivity access transistor, the low energy dopant can be an n-type dopant such as phosphorus, arsenic or antimony.
    Type: Grant
    Filed: May 24, 1993
    Date of Patent: April 11, 1995
    Assignee: Micron Technology, Inc.
    Inventors: Monte Manning, Charles Dennison, Howard Rhodes, Tyler Lowrey
  • Patent number: 5397721
    Abstract: A method for fabricating a vertical thin film transistor capable of improving a current driving capability. The method includes the steps of sequentially forming a source electrode and a high concentration n type doped, first semiconductor layer over a substrate, selectively removing the source electrode and the first semiconductor layer at their portions at which a gate electrode is to be formed, sequentially depositing an insulating film and a metal layer for the gate electrode over the entire exposed surface of the resulting structure and then selectively removing the insulating film and the metal layer to form the gale electrode, anodizing an exposed surface of the gate electrode to form a gate insulating film, depositing an intrinsic, second semiconductor layer over the entire exposed surface of the resulting structure and depositing a high concentration n type doped, third semiconductor layer over the second semiconductor layer, and forming a drain electrode over the third semiconductor layer.
    Type: Grant
    Filed: January 25, 1994
    Date of Patent: March 14, 1995
    Assignee: Goldstar Electron Co., Ltd.
    Inventor: Chang W. Hur
  • Patent number: 5395787
    Abstract: Shallow junctions n- and p-channel field effect transistors are formed with a single ion implant into a conformal tungsten silicide layer. Although phosphorous and boron are implanted into the same silicide regions, the phosphorous prevents the boron from outdiffusing.
    Type: Grant
    Filed: December 1, 1993
    Date of Patent: March 7, 1995
    Assignee: AT&T Corp.
    Inventors: Kuo-Hua Lee, Chun-Ting Liu, Ruichen Liu
  • Patent number: 5393676
    Abstract: A PMOS device is provided having a diffusion barrier placed within a polysilicon gate material. The diffusion barrier is purposefully implanted to a deeper depth within the gate material than subsequently placed impurity dopants. The barrier comprises Ar atoms placed in fairly close proximity to one another within the gate conductor, and the impurity dopant comprises ions of BF.sub.2. F from the impurity dopant of BF.sub.2 is prevented from diffusing to underlying silicon-oxide bonds residing within the oxide bulk. By minimizing F migration to the bond sites, the present polysilicon barrier and method of manufacture can minimize oxygen dislodgment and recombination at the interface regions between the polysilicon and the gate oxide as well as between the gate oxide and silicon substrate.
    Type: Grant
    Filed: September 22, 1993
    Date of Patent: February 28, 1995
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Mohammed Anjum, Ibrahim K. Burki, Craig W. Christian
  • Patent number: 5385851
    Abstract: In a method of manufacturing a semiconductor apparatus, a resist is coated on a semiconductor substrate and baked. The resist is exposed with an electron beam, and an invertedly tapered opening is formed. Recess etching is performed on the semiconductor substrate through the opening. An electrode is formed at a location determined by the recess etching.
    Type: Grant
    Filed: June 14, 1993
    Date of Patent: January 31, 1995
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroto Misawa, Hitoshi Tsuji
  • Patent number: 5385852
    Abstract: For manufacturing vertical MOS transistors, doped regions for a drain (11), well (3), and source (4) are formed in a vertical sequence in a substrate (1). Using a Si.sub.3 N.sub.4 mask (5), trenches (6) are etched perpendicular to the surface of the substrate (1). The trenches isolate the source (4) and well (3) structure, and are filled with doped polysilicon and are closed in an upper region with an insulation structure (8) in self-aligned fashion on the basis of local oxidation. The insulation structure (8) projects laterally beyond the trenches (6). Using the insulation structure (8) as an etching mask, via contact holes (9), that are provided with a metallization for contacting the source (4) and the well (3), are opened down into the well (3) between neighboring trenches (6).
    Type: Grant
    Filed: December 9, 1993
    Date of Patent: January 31, 1995
    Assignee: Siemens Aktiengesellschaft
    Inventors: Klaus-Guenter Oppermann, Wolfgang Roesner, Franz Hofmann
  • Patent number: 5382535
    Abstract: A transistor has a JFET gate region of a first conductivity type formed at the face of a semiconductor layer to laterally and downwardly surround a drift region of a second conductivity type. A thick insulator region is formed on a portion of the drift region at the face. A IGFET body of the first conductivity type is formed at the face to be adjacent the JFET gate region. This body spaces a source region of the second conductivity type from the drift region. A drain region is formed at the face to be of the second conductivity type and to adjoin the drift region, and to be spaced from the IGFET body. A conductive gate extends over the face between the source region and the thick insulator region, with a thin gate insulator spacing the gate from the IGFET body.
    Type: Grant
    Filed: March 16, 1994
    Date of Patent: January 17, 1995
    Assignee: Texas Instruments Incorporated
    Inventors: Satwinder Malhi, Wai T. Ng
  • Patent number: 5382536
    Abstract: A lateral DMOS (LDMOS) transistor 10 is disclosed herein. In one embodiment, an n doped silicon layer 14 is provided and a field oxide region 24 is formed therein. A p doped D-well region 20 is formed in the silicon layer 14 and includes a p doped shallow, extension region 22 which extends from the D-well region 20 to a first side of the field oxide region 24. A first n doped source/drain region 16 is formed in the D-well region 20 and is spaced from the field oxide region 24. Also, a second n doped source/drain region 18 formed in the silicon layer 14 on a second side of the field oxide region 24. A gate region 26 is formed over the surface of the silicon layer 14 and over a portion of the first source/drain region 16, the D-well region 20, and a portion of the field oxide region 24.
    Type: Grant
    Filed: March 15, 1993
    Date of Patent: January 17, 1995
    Assignee: Texas Instruments Incorporated
    Inventors: Satwinder Malhi, Michael C. Smayling, Stephen A. Keller
  • Patent number: 5378655
    Abstract: A mask (4) defining at least one window (4a) is provided on one major surface (1a) of a semiconductor body (1). The semiconductor body (1) is etched to define a groove (5) into a first region (2) of one conductivity type through a second region (3) of the opposite conductivity type. A relatively thin layer of gate insulator (6) is provided on the surface (5a) of the groove (5). A gate conductive region (7) of an oxidizable conductive material is provided within the groove (5) to define with the gate insulator layer an insulated gate structure (8) bounded by a conduction channel-defining area (30) of the second region (3). A step (15) in the surface structure is then defined by causing the insulated gate structure (8) to extend beyond the surrounding surface by oxidizing the exposed (7a) gate conductive material to define an insulating capping region (9) on the gate conductive region (3).
    Type: Grant
    Filed: March 31, 1994
    Date of Patent: January 3, 1995
    Assignee: U.S. Philips Corporation
    Inventors: Keith M. Hutchings, Kenneth R. Whight
  • Patent number: 5376559
    Abstract: A lateral insulating gate type field effect transistor can be manufactured with ease reliably by using a semiconductor substrate having excellent crystal property. A projected portion (2) is formed on a first major surface side of a semiconductor substrate (1). A first gate portion (3) having a width (length) smaller than that of the projected portion (2) is formed on the projected portion (2). An insulating layer (4) is formed on the whole surface of the semiconductor substrate (1) so as to bury the first gate portion (3). The semiconductor substrate (1) is removed horizontally from its second major surface side, i.e., from the opposite side of the side of the projected portion (2) to a position (a) at which the insulating layer (4) is formed so as to bury the projected portion (2) is exposed. A second gate portion (5) is formed on such exposed surface.
    Type: Grant
    Filed: December 27, 1993
    Date of Patent: December 27, 1994
    Assignee: Sony Corporation
    Inventors: Mikio Mukai, Masahiko Einaga, Yutaka Hayashi
  • Patent number: 5376589
    Abstract: Similar semiconductor chips (12-15), which are produced together on a plate and subsequently dissociated, are provided with identifying markings (17-20) containing their earlier position on the plate. If defects occur later in the dissociated chips, analyses can be made to determine whether defects occur with particular frequency in certain regions of the plate, or whether a statistical distribution exists.
    Type: Grant
    Filed: June 3, 1993
    Date of Patent: December 27, 1994
    Assignee: Robert Bosch GmbH
    Inventor: Christoph Thienel
  • Patent number: 5369060
    Abstract: In a method for dicing multi-layer composite wafers, proceeding from an upper side of the wafer, cuts are introduced into an upper layer of the wafer and, proceeding from a lower side of the wafer, cuts are introduced into a lower layer of the wafer.
    Type: Grant
    Filed: June 1, 1993
    Date of Patent: November 29, 1994
    Assignee: Robert Bosch GmbH
    Inventors: Helmut Baumann, Juergen Kurle, Peter Eiberger
  • Patent number: 5369045
    Abstract: A method of forming a LDMOS transistor device 10 is disclosed herein. A semiconductor layer 14 is provided. The layer 14 may be an n-type RESURF region formed over a p-substrate 12. An insulating layer 24, such as a field oxide, is formed on the semiconductor layer 14. The insulating layer 24 is then patterned to expose source and drain windows. A D-well region 20 is then formed within the source window portion of the semiconductor layer. A sidewall region is formed adjacent a sidewall of the insulating layer around the source window. The source and drain regions 16 and 18 are then formed, for example by implanting arsenic or phosphorus ions. A gate electrode 26 is formed over a portion of the D-well region 20 between the source region 16 and the insulating layer 24. The gate electrode 26 is formed over a channel region within the D-well 20 between the source 16 and drain 18.
    Type: Grant
    Filed: July 1, 1993
    Date of Patent: November 29, 1994
    Assignee: Texas Instruments Incorporated
    Inventors: Wia T. Ng, Oh-Kyong Kwon
  • Patent number: 5366914
    Abstract: In a vertical power field effect transistor, a side surface of a gate electrode is covered with a side oxide film, and a groove is formed in self-alignment with the side oxide film to extend from a surface area of a silicon substrate between a pair of adjacent gate electrodes, to reach a base region. A tungsten film is filled into the groove thus formed, and a source electrode-is formed in contact with the tungsten film within the groove.
    Type: Grant
    Filed: January 29, 1993
    Date of Patent: November 22, 1994
    Assignee: NEC Corporation
    Inventors: Nobumitsu Takahashi, Mitsuasa Takahashi, Hitoshi Kubota
  • Patent number: 5360749
    Abstract: A semiconductor structure with germanium implant is provided for reducing V.sub.T shifts at the channel edges thereby minimizing short channel effects and subthreshold currents at or near the substrate surface. The semiconductor structure is adapted to receive non-perpendicular implant of germanium in the juncture between the channel and the source/drain regions as well as in the juncture between field oxide channel stop implant and source/drain regions. By carefully and controllably placing the germanium at select channel and field regions, segregation and redistribution of threshold adjust implant and channel stop implant dopant materials is substantially minimized. Reducing the redistribution of such materials provides a reduction in the short channel effects and, particularly, a reduction in substrate surface current or DIBL-induced current.
    Type: Grant
    Filed: December 10, 1993
    Date of Patent: November 1, 1994
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Mohammed Anjum, Klaus H. Koop, Maung H. Kyaw
  • Patent number: 5358885
    Abstract: A method of producing a field effect transistor includes depositing a first insulating film and a refractory metal on a semiconductor substrate, forming a first aperture penetrating the first insulating film and the refractory metal film to provide a gate electrode production region, depositing a second insulating film on the refractory metal film, etching the second insulating film in a direction perpendicular to the surface of the substrate leaving portions of the second insulating film on opposite side walls of the first aperture to form a second aperture, defining a gate length, depositing a gate metal, and patterning the gate metal layer, the first insulating film, and the refractory metal film in a prescribed width to form a T-shaped gate structure. During etching the second insulating film, since the refractory metal film serves as a etch stopping layer, the first insulating film is not etched and its thickness remains as deposited.
    Type: Grant
    Filed: April 16, 1993
    Date of Patent: October 25, 1994
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tomoki Oku, Masayuki Sakai, Yasutaka Kohno
  • Patent number: 5344789
    Abstract: A semiconductor device includes an N.sup.- type semiconductor layer (2). The N.sup.- type semiconductor layer (2) includes a triangular pole trench (10), an apex portion thereof contains a gate electrode (5). The trench (10) penetrates the semiconductor layer (2) and a P type well region (3) and projects into an N.sup.+ type source region (4). A source electrode (7) is disposed so as to be insulated from the semiconductor layer (2) by an oxide film (9) and in contact with the well region (3) and the source region (4). A drain electrode (8) is connected to the semiconductor layer (2) through an N.sup.+ type semiconductor substrate (1). With higher potential at the gate electrode (5) than at the source electrode (7), the well region (3) is partially inverted into N type near the trench (10). Thus, the semiconductor device is turned on due to a channel created associated to the conductivity type inversion. Most of current flow allowed in the semiconductor layer (2) by the channel flows near the trench (10).
    Type: Grant
    Filed: November 23, 1993
    Date of Patent: September 6, 1994
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Tomohide Terashima
  • Patent number: 5342795
    Abstract: This is a method of forming a vertical transistor device comprising: forming an n-type first drain/source layer 42; patterning a portion of the first drain/source layer 42 to form a channel 44 and a trench; forming a p-type gate structure 46 in the trench; and forming a n-type second drain/source layer 48 over the gate structure 46 and the channel 44; contacting the gate structure 54; forming p-ohmic contact to the gate structure 56; forming n-ohmic source contact 54; and forming n-ohmic drain contact 58. Other devices and methods are also disclosed.
    Type: Grant
    Filed: November 15, 1993
    Date of Patent: August 30, 1994
    Assignee: Texas Instruments Incorporated
    Inventors: Han-Tzong Yuan, Donald L. Plumton, Tae S. Kim, Jau-Yuann Yang
  • Patent number: 5338703
    Abstract: In a method for producing a recessed gate field effect transistor including a recess in a semiconductor substrate and a gate electrode disposed in the recess, a photoresist film is applied to the semiconductor substrate and source and drain electrodes on the substrate, a first insulating film is formed on the photoresist film, a resist pattern, which has an opening for processing the first insulating film and the photoresist film are etched using the resist pattern as a mask to form an opening having a width increasing in the direction of the substrate, a second insulating film is formed on opposite side walls of the opening, the semiconductor substrate is etched using the opening narrowed by the second insulating film in the substrate to form a recess, the second insulating film is selectively removed by etching, gate metal is deposited on the photoresist and on the substrate in the recess, and unnecessary gate metal is removed by lifting-off the resist film.
    Type: Grant
    Filed: July 7, 1993
    Date of Patent: August 16, 1994
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Hiroshi Matsuoka
  • Patent number: 5326711
    Abstract: A transistor device (10) includes an epitaxial layer (14) formed on a semiconductor substrate layer (12). A base layer (16) is formed on the epitaxial layer (14) and a source layer (18) is formed on the base layer (16). A trench region (22) is formed extending through the source layer (18), the base layer (16), and the epitaxial layer (14) and into the semiconductor substrate layer (12). An oxide layer (24) is formed on the source layer (18) and on the internal walls of the trench region (22) such that the oxide layer (24) is wider at the bottom of the trench region (22) than at the top in order to handle high voltage applications. A gate layer (26) is formed within the trench region (22) on the oxide layer (24). The gate layer (26) causes a drift region formed within the epitaxial layer (14) to fully deplete under full rated blocking conditions, decreasing the drift region component of the on-resistance which is the dominant parameter in very high voltage devices.
    Type: Grant
    Filed: January 4, 1993
    Date of Patent: July 5, 1994
    Assignee: Texas Instruments Incorporated
    Inventor: Satwinder Malhi